Process of making acid or alkali resisting articles.



UNITED STATES P E T OFFICE.

ISAIAH I). ROBERTS, LOCKPORT, NEW YORK.

PROCESS OF MAKING ACID 6R ALKALI RESISTING ARTICLES.

No Drawing.

Specification of Letters Patent.

Patented May 16, 1911.

7 Application filed July 23, 1907. Serial No. 385,215. (Specimens) To all whom it may concern:

Be it known thatl, IsArAIr L. ROBERTS, a citizen of the United States, residing at Lockport, in the county of Niagara and State of New York, have invented certain new and useful Improvements in Processes for Mak ing Acid or Alkali Resisting Articles, of which the following is a specification.

My invention relates to articles of wood, wood-pulp, straw-board or other woody material, to be used with acids or alkalies-or both, and has for its object to provide an article for such purpose which shall be capa- 'ble of resisting the attacks of acids and alkal ies, and to provide an economical and easily practiced process or method for.mak-

ing such articles.

Heretofore numerous attempts have been made to utilize wood, wood-pulp, etc-., for articles to be used with acids and alkalies, for example, as containing receptacles or vessels for the same, but so far as I am aware none of these attempts has been wholly successful, A common method for the purpose is to coat the surface of the article, or to impregnate the article as deeply as possible, with acid and alkali resisting material; but it has been found that after an articleso treated has been in use for a more or less a carbonized, in the manner described in my prior application Ser. No. 253,384, filed April 3, 1905,patented October 5th, 1909, No. 936,039. To effect the partial carbonization the article is placed in an oven and heat applied, very slowly and evenly so that the article will'not be cracked by sudden change of temperature. As the carbonization proceeds the article shrinks more or less, but if the heating is gradual no splitting or crack-' ing will occur. The extent to which the heating should be carried, de ends in general upon the material of which the article is made, and the size thereof or the thickness ,of its walls, and for particular mate 1. The method of treating articles rials and conditions can best be determined by trial. In general it may be stated. that thecarbonization should proceed through-' out the entire body of material and until the article is porous, resembling charcoal in appearance, but must leave the article strong enough to serve its intended purpose. The cooling must also be slow and even, like the heating, to avoid the cracking which might be caused by sudden change of temperature.

The partially carbonized article is now treated, as for example by soaking or boiling, with an alkali or acid resisting substance or substances to render it impervious thereto. For this purpose the article may be.

immersed in liquefied .wax, such as paraffin,

beeswax, ozokerite, etc.; or liquefied tar, resin, asphalt'um, etc., sulfur, or even stearlc acid; until the pores of the article are per-. meated withthe ,resistant 'materialp-jlf desired, a mixture of two or more ofthe above substances may be used. For instance, as.- phaltum is more or less vlscous when melted, so much so as to be absorbed 1nto the-pores slowly; in this case resin and paraflin may" be mixed with the asphaltum insufficient quantities to give the desired fluidlty.

What particular substance or substances are to be used will depend somewhat upon the cost and weight thereof, but primarily upon the particular use for which the article is intended. For example, stearic acid and hydrocarbon waxes will resist practlcally all acids, but the paraflin waxes, or. sulfur, should be used if resistance to alkalies is desired.

When the article is well permeated the permeatingmaterial is allowed to harden, whereupon the article is ready for use. Such an article is completely impervious and resistant, resisting admirably even slow at tack on the surface fibers, and hence. has

very long life with strong acids or alkalies. The resistant substances hereinbefore named are the most suitablefor the and a number of them are very inexpensive; at the same time.they are not heavy enough to make the article inconveniently heavy. In general any im ervious resistant substance or mixture 0 substances can be used which can be liquefied, as by heat, or in a solvent, etc., and which will harden again in the pores of the article. What I claim is:

woody material to make the same liquidurposeproof and acid or alkali resistant, which consists" in partially carbonizing the article throughout the body of material, and then filling the pores thereof with resistant materiaL' 2. The method of treating articles of Woody material to make the 'same,liquidproof and acid or alkali resistant, which consists in partially carbonizing the article throughout the body of material, then filling the pores thereof with resistant material liquefied by heat, and allowing the material to harden in the pores of the article.

eoaaae 3. The method of treating articles of Woody material to make the same liquid 15 proof and acid or alkali resistant, which consists in gradually heating the article until partially carbonized through the body of material, and then filling the pores ofthe partially carbonized article with resistant 20 material.

ISAIAH L. ROBERTS.

Witnesses WM. H. BAKER, M. J. NELLIGAN. 

